In the manufacture of hollow glass articles, molding machines are used, in which the articles extracted from respective molds are first transferred onto a horizontal supporting plate, and from this onto an unloading conveyor belt. The hollow articles are transferred from the supporting plate to the conveyor by means of a push device, which pushes them along a substantially 90° arc.
The push device comprises one or more compartments, each bounded by two walls for supporting the article and which form a right-angle. As the compartment rotates along the transfer arc, the hollow article is retained inside the right-angle, resting against the walls, by a stream of compressed air flowing upwards along a substantially vertical channel defined by the walls on one side, and the hollow article on the other.
Though widely used, known push devices of the type described are not altogether satisfactory, by sometimes failing to hold the article stably inside the compartment, regardless of the shape/size of the article and the initial position of the articles with respect to one another on the supporting plate. To eliminate this drawback, the speed and/or pressure of the air are/is normally increased to increase the retaining force exerted on the article. This, however, often results in visible damage to the parts of the article contacting the supporting walls, thus resulting in poor-quality finished products.